During some recent testing, we discovered that two of the most critical icons in our application failed for color-impaired users. My current project is an accounting application which contains many screens that utilize a common pattern for adding and removing. This pattern makes use of individual icons for each action. The icon for add is a plus symbol set within a green circle and the icon for remove is an “x” set within a red circle.

To the majority of users there is enough contrast between the symbols and the color for the user to distinguish between the two icons and to use them confidently and accurately. For a color-impaired user, however, this is a much more difficult task.